If one could save only a single Coward play for posterity, it would have to be Private Lives (1930). Though Coward described it as “the lightest of light comedies”, the piece is a marvel, a work that transcends its period setting and still proves startlingly fresh, funny and unexpectedly moving. It needs to be played with the most delicate of touches, with speed, intelligence and style, but in really good productions, like this one, there is depth to the comedy, too, and a sense of darkness beyond the laughter.

Jonathan Kent directs one of the finest productions of the play I have seen, with tremendous performances from Anna Chancellor and Toby Stephens as the self-obsessed lovers, Amanda and Elyot, who can’t live together and can’t live apart.

Any staging of this play is a risk, because its success entirely depends on whether the actors playing the leading roles have the right chemistry between them. You really need to feel that this is a pair that have great sex together but drive each other mad when they aren’t in bed. Perhaps that’s precisely why the sex is so good.

Stephens and Chancellor ignite thrilling sparks even as they knock lumps out of each other. Theirs are the most persuasively sex-drenched performances in Private Lives since Alan Rickman and Lindsay Duncan set the West End ablaze 11 years ago.

In the great central act, post-coital languor gives way to seething irritation, as the pair wind each other up with sadistic precision, before exploding into no-holds-barred physical violence just as their abandoned new spouses make their splendidly timed comic entrance.

I haven’t seen Toby Stephens give a better performance than he does here, following in the footsteps of his parents, Robert Stephens and Maggie Smith, who were a famous Elyot and Amanda in the Sixties.

Right from the start he suggests an edge of danger beneath Elyot’s witty well-spoken manner, gazing on his vacuous new wife as if she were a porcelain doll that part of him would already like to smash. This is a man who really believes “that certain women should be struck regularly, like gongs”. The miracle is that Stephens’s Elyot combines such sentiments with sudden moments of heart-melting charm.

Anna Chancellor is equally fine as Amanda, palpably and unashamedly beyond the first flush of youth, and already recoiling from her ploddingly conventional new husband Victor’s touch in the first act. There is truth as well as wit in her declaration she is “jagged with sophistication” and the coup de foudre when she catches sight of Elyot is palpable.

These thrilling star performances are accompanied by fine work in the supporting roles. Victor may be a dull old stick but Anthony Calf memorably captures his decency, too, while Anna-Louise Plowman’s shrill, whining Sibyl makes you feel she deserves everything she gets.

Kent’s constantly alert and gripping production is further enhanced by Anthony Ward’s stylish designs and music ranging from Django Reinhardt to Stravinsky as well as Coward himself. This is a show that offers two hours of continuous pleasure.